A running account of the building of my Hub Center Steered, Smart CDI Engine,Bio Diesel Powered,
Custom construction Bonneville land speed motorcycle project.
I had to modify the front swing arm brace to make it
something that I could easily make. In fact the modified part is simpler and
was easier to make than my original design. By making the brace tube a single
piece with a 192degree bend I was able to make more quickly and more accurately
than the previous 3 piece welded design. I call this piece a brace but actually
it’s main function is as the mount or actuator for the front shock. The swingarm
main tubes are easily beefy enough for the job especially since there will be
no braking forces (no front brake) and the lateral forces will be small
compared to a street bike that is designed to go around corners. Any lateral forces induced by turning or lean
angle will be due to coarse correction or cross wind compensation and should be
much smaller than what the forks of a street or track bike have to deal with.
Top Loop Against the Drawing
Loop In the Lathe Notching Jig for First Cut
Squaring up the top loop in the lathe Jig
The Bosch DWM 40L. Extremely useful for this kind of work. Far more accurate and versatile than a combination protractor square.
Turned Inserts for the 5/8” Heim joints from 8620 steel.
These fit into the 1-3/8” tubing and are welded into place. This will allow
some adjustment of the front swingarm and make it easier to get the swingarm
square with the frame and the rear swing arm pivot. These are from summit
Racing and are similar to the Aurora HXMA Series Rod End Bearings though these have
a radial Load Capacity of 21000Lbs.
Fine tooth (10tpi) hole saws make a huge difference when
mitering thin wall tubing. It was the difference
between a smooth accurate cut and the saw grabbing and coarsely cutting through the material occasionally breaking a
tooth along the way.
The Under utilized JD2 Model 32 bender on my home made stand
I Bought this over a year ago for another project that is now on hold. these benders are relatively inexpensive and do a great job of easily bending even large diameter tubing. I'm doing 1.375x095 at the moment and was surprised at how easy it was to bend compared to the Diacro bender I had been using. In all fairness the Diacro was never meant to bend tubing larger than 1 inch or so. However with the JD I didn't even have to use a cheater pipe on the relatively short handle as it gives you that much leverage. And with the added leverage ratio also comes more precise control over the bend.
First miters cuts of the day
.
Here is the first bend of 1.375"x.065 wall. it's a 6.5" Center line radius with a 1.375" miter on each end. this is the center brace for the front swing arm which is the first frame piece I decided to make. That decision was based mostly on the fact that the other components are still in the design phase and subject to change where as the swing arm is done the drawings ready to go. Below is an image of the weldment model of the front swing arm so you can see where the parts I'm making here fit together.
Front Swing Arm Model In Solidworks
I am a complete green horn when it comes to working with
tubing (even worse at laying out blog posts I might add). That said one of the fun challenges for me is figuring out how I’m
going to accurately miter the tubing so that it fits together the way I have
designed it. The videos on Youtube from guys trying to sell you a tube notcher show miters that are all dead easy to make. Most of the commercial notchers aren’t
capable of making a very shallow miter cuts on a tube that already has a bend in it.
They can’t be adjusted for cuts shallower than about 35 degrees, and only the very
expensive ones can hold bent or non straight tubing. Hole saws also need a very
ridged set up to cut well so again all but the expensive tube notchers out
there aren’t very good in that department either. Motorcycle frames need to be much
more accurate than roll cages or furniture, so starting with really precise
clean cuts makes a huge difference. I've seen tutorial vidios on equipement manufacturrers web sites that show miters with large gaps between the tubes where the guys calmly states that he will just fill the hole when he welds the pieces together. Huge FAIL in my book. When it comes to a ridged set up a Bridgeport
makes and excellent hole saw and that is what I used for the 2 cuts on the
1.375 cross brace. The 1 inch top loop brace is really for mounting and actuating
the front Shock more than it is for actually stiffening the front swing arm. Where
it meets the 1.375” main tubes is a shallow 15deg angle that produces a fairly long cut. I couldn’t think of an
easy way to do this on the Bridgeport but had seen a notching system for using
a lathe that seemed to offer an excellent solution (again a nice heave ridged
machine tool). In the VMC I drilled and tapped a .75” piece of 7075 Aluminum
with an array of ½-13 holes with some reamed 1.4” holes forfor pins for locating the work piece. There is a
counterbored piece that bolts to the back of the plate that allows the whole
fixture to be clamped into one of the Aloris tool holders so that it can be
placed on and off the Aloris tool post easily. Moving the lathe compound slide
is a very easy way to get very accurate angled cuts and also makes it very easy
to adjust precisely where the saw starts to cut through the tube. Here you see
the shallow 15degree cut that was actually very easy using this set up.
A Nice Fit
Some of the front swing arm parts ready for welding
As much as I hate quoting the vapid philosophy of pop songs,
they do sometimes sum up a thought or two nicely for you when you are too lazy
to think of anything pithy yourself. Two such came to mind as I was preparing
to write this. An abbreviated version John Lennon (or Allen Saunders) starts us off “Life is what happens when you‘re
making plans”. And the corollary question: How do you make god laugh? The point
of all this is that I have been working elsewhere for another company at their shop in Brooklyn,
and don’t get to my shop at all these days. I finally managed to get a couple
of days to work on the bike and the following is what I have to show for it.
This is the king pin or pivot for the hub center front end. It is the 1st
op turned from 8620 steel. There will be a 1 inch hole bored through the center
and 2 flats machined on the ball to provide faces for the axle spacers to
locate on. This will hold the wheel in the center of the axel. As you can see
it fits into a top and bottom tapered roller bearing which get loaded together via
bolts that run through the hub and pull together the 2 “caps” that hold the outer
races. As it turns out this is very similar to the front end that DiFazio filed
a patent for in 1968. A copy of which is on line here:
I know I should be modeling frame rails and other bits instead of playing around with rendering but I decided to screw around with photos view 360 little bit tonight. It does produce some very pretty pictures even though I have no idea what I'm doing. In the hands of some one with a rendering clue it can produce some very convincing images. This is the new rear spindle assembly with a Kawasaki gear designed to fit the BMW main bearing with a hub and bolt pattern that fits the BMW rear wheel. It will allow me to keep the same offset for the swing arm and the BMW transmission and still use the BMW rear wheel. What you see here is some renderings of rear bearing assembly as well as a video of the first operation cutting the spindle out of a piece of 4140 steel. The next operation was to move it to the mill where the wheel lug holes were drilled and tapped and some lightening grooves cut in. Next it will be put back in the lathe, flipped around and have the shaft part turned down. That is the spindle that goes into the small Timken bearing and has a threaded section for the nut that captures the main drive gear.
First Op on the rear spindle. From a 3.5" billet of 4140 steel.
The drive gear with pins installed and the retaining
nut I made with a 26x1mm ID thread
Boy how I love and Hate CNC tapping. Having broken a few taps, I am scared poopless every time I push the go button on an unproven tapping cycle. When it works it's a thing of beauty. When it fails, you get to watch your machine mercilessly grind a poor tap into your now ruined work piece while you stand there helpless. This time however I got it right.
Second op done. Next step is to turn the skinny end.
Things are looking more cohesive. I took a small library of pictures to use as references for modeling some parts and for layout of other parts like the rider position and subsequently the frame.With these images I can roughly determine the engine position and where the front wheel and front swing arm will be which will allow me to play with the preliminary shape of the body work. It will also allow me to start laying out the controls and start planning spaces for all of the components such as the cooling system, fuel tank and air tank that will all need to ne nested within the bodywork.
Taking pictures of the rider (me) on the rider position jig. it was 105 Degrees F in the shop and as humid as a roman bath. I really need to get a remote control for the D80. Yes I have 2 digital cameras. BTW this in HD if you want to really see the detail of me sweating like Al Goldstein.
This is a rendering of the model of the oil pan. as you can see in the previous post the engine is canted forward at about 9.5degrees and this oil pan is designed with that in mind. I have a block of MDF waiting to be machined so that I can prove fit and machining strategy before I destroy a $100+ chunk of Aluminum. Photos as soon as I get the time to actually make it.
I have been working for a new employer and time to work on the project has been very scarce. On top of that funding has been uncertain at best. However that should soon change with this new job. I have a number of parts designed and ready to machine including the new oil pan, a new transmission adapter plate that has redesigned motor/frame mounts and a number of more ancillary bits. I also need to make the axle and get the hub center front end finished up. I did get the chance to stop by the shop and take some pictures. What you see here is the engine, transmission and rear drive assembled and mounted to the frame table/jig. There is a wooden fixture to do some preliminary rider position layouts and position the front wheel. I have a vinyl cutter and used it to layout a graduated size reference so that I could accurately size the images in Solidworks to use as a sketch background for frame layout ideas.
Autodesk, the makers of AutoCAD (among other apps) is offering a free Beta test of their new photo to 3D model service called Photofly http://labs.autodesk.com/technologies/photofly The idea simply is that you take a number of pictures of something for 3620 degreed around it, upload it to their photofly cloud service and within minutes you get a 3d Mesh model of whatever it was you took pictures of. I've been trying it out and it does work though there seem to be a lot of variables to account for in order to achieve success though it really isn't that difficult. I have gotten pretty good results so far with the only real disappointment being the attempts at getting a 3D model of my 4 year old Otto. To his credit he actually held very still (for a 4 year old) and his body came out pretty good on the 2 times I have tried to do this so far. His face and head didn’t fair so well due to his fascination with what I was doing and his inability to keep a straight face. I'd probably have better success with him if I wasn't making goofy noises and talking to him while I tried to photograph him but I digress. I still think I can get a good model so I'll try again now that I have my good camera with me. Speaking of good cameras, the image quality doesn’t seem to be as important as you'd think as long as your subject is in focus. That said, having a good camera, like my Nikon SLR, which can take 40+ images with a single push of the shutter button really helps. This is because all you have to do is frame your shot, then keep your aim as you walk around the subject as the camera records the images. What does all this have to do with a diesel motor land speed record bike you ask? Well I have always wanted a 3D model of the smart motor. I’m not about to pay a scanning service to do one and my Solidworks skills aren’t good enough to do it free form as it were. On top of that it isn’t really nessicarry to the project. I just want it to add authenticity to the 3D model and to the assembly model of the bike I build as I design parts for the project. So here I am taking the bare Smart engine Block I have out to the back parking lot via the freight elevator so that I can get some good pictures if it. The lighting in the shop isn’t great to take pictures by especially taking bursts of images where you need a fast shutter speed to keep the image from blurring as you move around the subject. For a really good overview/tutorial, my friend Adam has done this video:
